PackageNamesChecker default regex allows uppercase

[anilkumarmyla]

As per scala/java naming conventions, package names are written in all lower case. But the default regex and documentation point to a regex that allows camelcase package names

class PackageNamesChecker extends ScalariformChecker {
val DefaultRegex = "^[a-z][A-Za-z]*$"

[matthewfarwell]

Thanks. Do you want to do a PR for this?

[anilkumarmyla]

I'll give it a try!

[mwz]

This was released in https://github.com/beautiful-scala/scalastyle/releases/tag/v1.3.0.